You can uninstall or removes an installed pkg-config-powerpc-linux-gnu package itself from Ubuntu 14.04 LTS (Trusty Tahr) through the terminal,
$ sudo apt-get remove pkg-config-powerpc-linux-gnu
If you would like to remove pkg-config-powerpc-linux-gnu and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove pkg-config-powerpc-linux-gnu
If you use with purge options to pkg-config-powerpc-linux-gnu package all the configuration and dependent packages will be removed.
$ sudo apt-get purge pkg-config-powerpc-linux-gnu
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove pkg-config-powerpc-linux-gnu